Arborist Reports: What They Are and When You Need One

An arborist report is a formal written assessment prepared by a qualified arborist that evaluates a tree's species, health, structural condition, useful life expectancy, and any risks it poses. These reports are most commonly required by NSW councils as part of development applications (DAs), tree removal permit applications, and property transactions. A standard arborist report typically costs between $300 and $800 depending on the number of trees and complexity of the assessment.

In my work across the Central Coast, Lake Macquarie, Newcastle, and Sydney's North Shore, I prepare arborist reports regularly. They are one of the most important documents in the tree management process, and understanding what goes into them helps you know when you need one and what to expect.

What an Arborist Report Includes

A comprehensive arborist report typically covers the following:

Tree Identification and Inventory

- Species identification -- Both the common and botanical name of each tree assessed.
- Tree dimensions -- Height, trunk diameter (DBH -- diameter at breast height), and canopy spread.
- Location mapping -- The position of each tree relative to structures, boundaries, and other features. This often includes a site plan or tree location map.

Health and Condition Assessment

- Vitality assessment -- An evaluation of the tree's overall health, including foliage density, colour, and growth patterns.
- Structural assessment -- Examination of the trunk, major limbs, and root zone for defects such as decay, cracks, cavities, included bark, or co-dominant stems.
- Pest and disease -- Identification of any pathogens, insect damage, or fungal infections.

Risk Assessment

- Likelihood of failure -- Based on structural defects, species characteristics, and environmental exposure.
- Consequences of failure -- What could be damaged if the tree or a limb failed, including buildings, footpaths, and high-use areas.
- Overall risk rating -- Usually categorised as low, moderate, high, or extreme following an established framework such as QTRA (Quantified Tree Risk Assessment) or TRAQ (Tree Risk Assessment Qualification).

Recommendations

- Retain, remove, or manage -- A clear recommendation for each tree.
- Pruning specifications -- If pruning is recommended, the type and extent in accordance with AS 4373.
- Protection measures -- For trees to be retained during construction, a Tree Protection Plan specifying protection zones, fencing, and ground protection.
- Useful life expectancy -- An estimate of how many years the tree can be expected to remain viable.

When Do You Need an Arborist Report?

Development Applications (DAs)

Most NSW councils require an arborist report as part of any DA where trees will be affected by the proposed development. This includes:

- Trees that will be removed to make way for construction.
- Trees on the site that will be retained but could be impacted by excavation, level changes, or construction activity within their root zone.
- Trees on neighbouring properties whose root zones extend into the development site.

On the Central Coast and in Ku-ring-gai, I regularly prepare reports for residential extensions, new builds, pools, and driveway works. If your project is anywhere near a significant tree, your council will almost certainly require a report.

Tree Removal Permit Applications

When you apply for a permit to remove a protected tree, council often requires an arborist report to justify the removal. The report needs to demonstrate that the tree is dead, dying, dangerous, or otherwise meets the council's criteria for removal. Read more about this process in our guide on council approval for tree removal in NSW.

Neighbour Disputes and Legal Proceedings

If you are taking a tree dispute to the NSW Land and Environment Court under the Trees (Disputes Between Neighbours) Act 2006, an arborist report is effectively essential. The Court relies heavily on expert arboricultural evidence. See our guide on neighbours' overhanging trees and NSW law for more context.

Property Purchases

Some buyers commission arborist reports before purchasing a property, particularly if there are large trees near the house or if they are planning renovations. The report can identify potential issues like root damage to foundations or trees that may restrict future development.

Insurance Claims

After storm damage or a tree failure event, an arborist report can document the condition of the tree before and after the event, supporting your insurance claim.

Who Can Prepare an Arborist Report?

For council submissions and legal proceedings, the report generally needs to be prepared by an arborist holding a minimum AQF Level 5 Diploma of Arboriculture, or equivalent qualification and experience. Some councils accept reports from AQF Level 3 arborists for straightforward tree removal permits, but DA-related reports typically require a consulting-level arborist.

It is important to understand the distinction between a certified arborist who performs tree work and a consulting arborist who prepares formal reports. Some arborists do both, while others specialise.

How Much Do Arborist Reports Cost?

Costs vary based on the scope of work:

| Type of Report | Typical Cost Range |
|---|---|
| Single tree removal assessment | $300 -- $500 |
| Multi-tree DA assessment (small site) | $500 -- $1,000 |
| Full arboricultural impact assessment (large site) | $1,000 -- $3,000+ |
| Tree Protection Plan for construction | $500 -- $1,500 |
| Expert witness report for Court | $1,500 -- $5,000+ |

These are general ranges. The cost depends on the number of trees, the complexity of the site, and whether the report requires follow-up inspections such as resistograph testing or aerial inspection.

How to Commission an Arborist Report

Here is the process:

1. Contact a qualified arborist and explain what you need the report for -- DA, removal permit, dispute, or other purpose.
2. Provide relevant documents -- Site plans, DA drawings, council correspondence, or any other context that helps the arborist understand the scope.
3. Site inspection -- The arborist will visit your property to assess each tree in person. This usually takes one to three hours depending on the number of trees.
4. Report preparation -- Allow one to two weeks for the report to be written. Complex reports with multiple trees or construction impact assessments may take longer.
5. Review and submission -- The arborist provides the final report for your review, and you submit it to council as part of your application.

Tips for Getting the Most From Your Report

- Engage the arborist early -- Before you finalise building plans. Sometimes a small adjustment to a building footprint can save a significant tree and avoid council objections.
- Be honest about your goals -- If you want a tree removed, say so. The arborist's job is to provide an honest, independent assessment, but knowing your intentions helps them address the relevant criteria.
- Keep the report current -- Most councils expect reports to be less than 12 months old at the time of submission. An outdated report may need to be updated.

Need an Arborist Report?

Whether you are preparing a DA, applying for a tree removal permit, or need an assessment for a property purchase, we can connect you with qualified consulting arborists across the Central Coast, Lake Macquarie, Newcastle, and North Shore. We also provide practical tree assessments for tree removal and tree pruning recommendations.

Call Daymian on 0432 687 647 or contact us online to discuss your requirements.